"Together we repudiate today a legacy of rancour and hatred which has torn asunder the fabric of our nation for decades," he said.

Norwegian diplomats, who have been mediating in the conflict, have warned it might take years before a final settlement is reached.

However, the United States has said it is hopeful of a desirable outcome this time.

Face to face

The organisers say the four delegates from each side will sit facing one another at the negotiating table, with Norwegian diplomats present, during the 12 hours of talks spread over three days.

Diplomats have warned that this phase of negotiations is expected to last months, if not years, and it may be much longer before a final political settlement is in place.

Prime Minister Ranil Wickremesinghe

The BBC's Frances Harrison in Pattaya says this echoes words of caution from members of the government delegation, who have said the peace process had to be stable and steady and would not bring quick results.

But there is also a great deal of optimism that this, the fourth attempt to end the Sri Lankan civil war, will eventually succeed.

A permanent ceasefire has held for seven months and the Sri Lankan Government has done away with many punitive measures imposed on rebel territory, where up to half a million people live.

Freedom

Freedom of movement has been restored across the island, with thousands of people daily crossing what were once front-lines and being reunited with lost family and friends.

Reconstruction work has begun on a limited scale in the conflict area, but the Sri Lankan government estimates it needs half a billion US dollars to rebuild the basic infrastructure in the north and east.

Government officials say there is now a convergence of factors that make an end to the war more likely.

Overwhelming support

Opinion polls suggest the Sri Lankan public and especially the business community, overwhelmingly supports a negotiated settlement now.

The American-led war on terror has made it more difficult for the Tamil Tigers to pursue their goal through military means, when they are banned in many western countries as terrorists.

And a new government in Colombo seems to have abandoned its predecessor's approach of trying to weaken the Tigers on the battlefield so as to force them to the negotiating table.

The result in recent months has seen an increase in informal contacts between high-level officials on both sides and a growing rapport emerging in their public statements.